Certain conditions of travel and/or certain geometrical and structural configurations of a boat of the type indicated above lead to excessive bucking of the planing boat. In particular, boats of short length, loaded at the rear, have a significant tendency to buck. A boat which, when planing has a significant tendency to buck, hits the wave violently on the surface of its hull and, under the influence of repeated impacts, becomes difficult to steer accurately.
It is possible to cancel out or at least reduce the buck of a planing boat by fitting the rigid hull with at least one flap which extends the submerged hull to the rear beyond the transom: such a fitting, which remains structurally simple, is entirely satisfactory in stabilising the boat, in particular for boats of relatively short length which tend to buck easily.
However, the flap(s) is/are, in currently known implementations, constituted by one or more separate parts which are connected to the lower edge of the transom in such a way that they extend beyond it to the rear, in the approximate prolongation of the rigid submerged hull, and which are bolted onto the transom.
The visible joint between the flap(s) and the transom and also the visible bolts spoil the aesthetic appearance of this part of the boat, being all the more visible as it can be located at eye-level when a small boat is hauled on board a larger vessel for use as a lifeboat.